The new cultivar was discovered as a result of a planned breeding program directed by the inventor, Ushio Sakazaki, a citizen of Japan. The seed parent is an unnamed, unpatented Phlox subulata and the pollen parent is an unnamed, unpatented variety of Phlox stolonifera. The cross resulting in ‘PPPHL0604’ was made Apr. 10, 2005. The new variety was discovered Sep. 15, 2006, by the inventor in a non-commercial nursery in Higashiomi Shiga, Japan.
Asexual reproduction of the new cultivar ‘PPPHL0604’ by vegetative cuttings was first performed Sep. 20, 2006 at a non-commercial nursery in Higashiomi Shiga, Japan. Multiple generations have since been produced and have shown that the unique features of this cultivar are stable and reproduced true to type in successive generations. The new cultivar was first sold and made available to the public in April 2011.